The present invention is generally directed to the control of odors resulting from the decomposition of human efflux, and in particular, the effect of a hydroxydiphenyl ether in a modified acidic environment applied to a personal hygiene product to control odors resulting from autolytic and enzymatic decomposition of human exudates and excreta into volatile nitrogenous byproducts.
Disposable absorbent personal hygiene products are designed to capture and retain human excreta in a convenient and in-expensive article. Advances in performance have been made in disposable diapers, adult incontinence pads and feminine hygiene products to further improve waste acquisition and maintain skin wellness. Enhanced top-sheet layers have been introduced that reduce the contact abrasion due to friction of the personal hygiene against one""s skin. Transfer intermediate layers are constantly in development whereby the waste, and in particular urine, is quickly wicked from the top-sheet to an absorbent core material. Improved core materials are available that can retain a liquid insult in spite of external compressive forces. While such advances have improved physical performance with regard to liquid and solid wastes, the decomposition of those wastes into volatile byproducts has been addressed with only limited effectiveness.
Disposable diapers and adult incontinence pads have improved in retention capability and can be worn for longer periods without loss of waste containment. While issues related to containment have improved, the development of odors remains a problem.
Urine, a primary form of liquid waste encountered by diapers and incontinence pads, is comprised in significant part of urea. The decomposition of urea results in the formation of volatile nitrogenous byproducts, most notably being ammonia, which are particularly malodorous.
Prior attempts to control ammonia odors have met with limited success. Sequesterants, such as cyclodextrins and zeolite clays are effective only in xe2x80x9ccapturingxe2x80x9d the ammonia once formed. If the structure of the sequesterant becomes occluded or contaminated by the presence of the complex milieu of proteins and salts found in urine, functionality is significantly degraded. The use of acids to shift the pH of the urine insult, and thereby protonate the ammonia into a nonvolatile ammonium ion, has been tried with variable results due, once again, to the chemical complexity inherent to urine. The most practiced method for controlling malodorous decomposition byproducts has been the use of perfumes and fragrances. This practice, however, has generally been found unsatisfactory as ammonia odors are particularly pungent and difficult to mask.
An alternate method by which ammonia odor may be controlled is to target the degradation pathways which produce ammonia.
Autolytic degradation of urea into ammonia occurs when urea is exposed to oxygen. In the environment of a personal hygiene product, and specifically in the fibrous component of a disposable diaper or incontinence pad, urine is wicked into interstices of the product""s high loft structure. These interstices form micro-environments where urea autolysis then occurs.
Enzymatic decomposition is an active process induced by specialized enzymes found in bacterial flora. Many genera of bacteria are ubiquitous to the human skin, the gastrointestinal tract, and the uro-genital tract as well as in the form of environmental contaminates found in the personal hygiene products itself. A general category of enzyme present in this flora allows for the breakdown of urea into ammonia. This enzyme is referred in general as a catalase, and specifically as an urease. When there is a liquid insult onto the hygiene product, bacteria are carried along with the liquid front and into the interstices of the fibrous construction. Ureases in the bacterial burden are active during this period, adding significantly to the production of ammonia. Certain bacteria are particularly receptive to this environment and will thrive, blooming the bacterial count and further increasing urea decomposition over time.
Various attempts have been made to control bacterial metabolism and bacterial growth, and thereby reduce odors. As in ammonia protonation, the use of acids as a topical treatment is a relatively effective means for skewing the pH of the environment and imparting a deleterious effect on bacterial health. However, problems in attaining and maintaining a desired pH range against the broad range of urine chemistries encountered in the human population is not trivial. Further, producing a uniform distribution of the acid treatment so as to equally effect all microenvironments is complicated by the solubility of the acid.
There remains an unmet need for an effective treatment for controlling noisome decomposition byproducts, and specifically those byproducts which are ammonia-based, from developing in soiled personal hygiene products. The odor control mechanism must exhibit sufficient robustness in the face of highly variable human waste chemistries while retaining stability during the hygiene product""s shelf-life. The present invention addresses these issues through use of a hydroxydiphenyl ether in a modified acidic environment.
The present invention is directed to the control of noisome odors created by the decomposition of human waste in a personal hygiene product. Control of the decomposition process is by the pre-application of an odor control compound comprising a hydroxydiphenyl ether in a modified acidic environment to one or more components of the personal hygiene product. The odor control compound exhibits a multi-functional performance, affecting not only the odiferous decomposition byproducts, but the biochemical decomposition and degradation pathways.
Human excreta and exudates are received and absorbed into the personal hygiene product. A particularly problematic human waste control issue involves a urine insult in a diaper or incontinence pad. FIG. 1 and FIG. 2 shows typical hygiene product constructions, whereby the urine contacts 10 or 14 a proximal surface of the hygiene product, then wicks through that surface and one or more other dispersing layers, eventually being absorbed into the structure of a 12 lofty fibrous core. Upon leaving the human body and being sequestered into the 12 absorbent core, the constituent chemistry of the urine begins to decompose. Urea, a compound comprising a significant amount of the urine chemistry, decomposes by autolytic and enzymatic mechanisms. The urea is broken down into nitrogenous volatile byproducts, most notably being ammonia. As ammonia evolves out of the solid hygiene product, both malodorous and detrimental skin-wellness effects occur.
By employing the compound of the present invention in one or more layers of the personal hygiene product, the production of ammonia is significantly curtailed. The hydroxydiphenyl ether reduces the metabolic performance of bacteria present in the environment. The presence of the hydroxydiphenyl ether in a modified acidic carrier further improves the bacteriostatic performance of the ether as well as introducing a pH shift that disfavors the further release of ammonia by inducing protonation of the ammonia into a nonvolatile ammonium ion.
The hydroxydiphenyl ether can be present in conjunction with the modified acidic carrier or located within immediate proximity. A preferred embodiment involves the admixing of the hydroxydiphenyl ether with the modified acidic carrier in an aqueous solution. This aqueous solution can then be applied to one or more layers of the personal hygiene product prior to or during product fabrication. Alternately, the hydroxydiphenyl ether can be incorporated into the polymeric composition prior to the formation of that composition into a construct, such as a fiber, filament or film, with the modified acidic carrier being applied topically thereafter. As the hydroxydiphenyl ether blooms to the surface of the construct, interaction with the modified acidic carrier can readily occur.
Other features and advantages of the present invention will become readily apparent from the following detailed description, the accompanying drawings, and the appended claims.